When their Premiership rivals Chelsea FC take on AS Monaco FC in the UEFA Champions League semi-final next week, everyone connected with Arsenal FC will look on with a mixture of envy and frustation.

Brave faceSince Arsène Wenger's men came up short in Europe's premier club competition with a 3-2 quarter-final defeat by their neighbours from across the capital, the coach has insisted that winning the Premiership title is the most reliable barometer of a team's consistency over a season.

European pedigreeBut the fact remains that no side can truly be described as great until they have succeeded in the Champions League, overcoming the different styles, tactics and techniques of Europe's finest. Arsenal may be great in terms of what they have achieved in England but it is European success at the highest level that counts. Wenger, privately, knows this. "I cannot deny that the Champions League is a little obsession for us," he admitted after the Chelsea defeat.

Physical fatigueHowever, in the coach's defence, midway through a run of four important games in eight days, Arsenal were arguably in no fit state to contest such an important match at Highbury. "I think we went into those two games without being at our best physically," said the Frenchman.

Under pressureYet there is more to Arsenal's dramatic undoing than fixture congestion. Without pressure on them, Wenger's team can overwhelm most opponents, but in Europe fear seems to grip Arsenal at the worst possible moments. When Thierry Henry was substituted against Chelsea, you could almost sense Arsenal's spirits draining.

Own worst enemyNo matter how many English championships Arsenal collect, their habit of shooting themselves in the foot has left many doubting whether they can ever justify comparisons with the likes of Real Madrid CF and AC Milan. Their attacking prowess notwithstanding, Arsenal too often appear one-dimensional against the very best sides.

Treasure chestChelsea, by contrast, have looked better equipped all season to challenge for European rather than domestic honours. Part of the reason has got to do with the type of player at each club. Chelsea, thanks largely to Roman Abramovich's treasure chest, have been weaned on different tactics and formations. Strength in depth is another vital commodity.

Core playersFor all their dominance of the Premiership, scratch beneath the surface of the regular first-team squad and Arsenal's resources are fairly slender when it comes to the Champions League. There is no obvious cover for Henry, Patrick Vieira or Sol Campbell, and Wenger's team can be badly exposed when they do not have the ball.

Top prize"I'm a great believer in statistics and if and when Arsenal win the Champions League, I would say they probably are the best team ever in English football, but you have to win the biggest prizes to be called a great team," said George Graham, the last consistently successful Arsenal manager.

Another chance?"Arsène is an outstanding manager," added the Scot. "He's won everything domestically but he's a student of the game and I would think he would want Arsenal to be on top in Europe as well." This was the season it was all supposed to come good - the question now is whether they will ever have a better chance.

The UEFA word, the UEFA logo and all marks related to UEFA competitions, are protected by trade marks and/or copyright of UEFA. No use for commercial purposes may be made of such trade marks. Use of UEFA.com signifies your agreement to the Terms and Conditions and Privacy Policy.